"Everything is in place," said Brandi Childress, an authority spokeswoman. "We're literally 60 days away. We're looking at groundbreaking in April."

The $2.3 billion San Jose extension will be built by the authority then incorporated into the BART system. It will start at the end of the Warm Springs extension, now under construction and expected to be completed in 2014, and reach 10 miles into Santa Clara County, ending, for now, on the east side of San Jose. Two stations are planned - one in Milpitas near the Great Mall with the other at the end of the line in the Berryessa neighborhood, across the street from the San Jose Flea Market.

The authority last month awarded a contract to build the extension, which could be completed by the end of 2016. A second phase, taking the extension another 6 miles into downtown San Jose and Santa Clara, would follow when funding is available.

BSV Conceptual Video of Milpitas Station

Media: San Francisco Chronicle

Aside from the federal funding, the bulk of the extension and the cost of operating it will be paid for by sales taxes approved by Santa Clara County voters in 2000 and 2008. About $649 million will come from the state.

While the federal funding is subject to congressional approval, it is usually routinely approved, Childress said.

"It would be unprecedented if we did not get this approval," she said. "That's never happened in the past."

But South Bay BART backers aren't taking any chances. Carl Guardino, chief executive officer of the Silicon Valley Leadership Group, a South Bay tech-industry organization that has pushed for the BART extension, is headed to Washington today to meet with congressional staffers, answer questions and deliver the message that tech businesses support the project.

Congress' role, said Guardino, is supposed to be limited to commenting on the funding plan, not approving it or rejecting it.

"But we want to make sure they know that there are very solid reasons this project has been supported by the leaders of the Silicon Valley economy for the past 12 years," he said. "This ball's being carried across the 1-yard line, and we want to make sure it gets into the end zone."